Originally, the area of Piraeus served essentially as an island with little connection to the mainland. At the advent of the classical era, this area between Piraeus and the shore silted and dried up enabling people to easily access the island. In 493 B.C. Themistocles advised Athens to utilize this area as the main naval headquarters and create a port city as well. He noted the 3 main harbors are were easy to access and deep enough for large vessels. In addition, Munichia (a large hill inland) and the rocky shore would make it difficult for foreign enemies to invade the city. This was a major difference between the old Athenian port of Phalerum which featured wide sandy beaches.

After a strategic defeat of the Persians at the Battle of Salamis in 483 B.C. Piraeus was permanently appointed as the main naval base for Athens. This victory also spawned Themistocles to fully protect the city by building the long walls to Athens and build the Themistoclean walls around Piraeus itself. At the beginning of the Peloponessian War, however, Sparta was able to take advantage of the weak naval force (due to the ongoing Athenian plague at the time) and blockade the city. Much like their tirade at Athens, The Spartans burned down the city wall, the Long Walls, buildings, weapons, and most important, the large trireme vessels. Although General Conan was able to take back Piraeus towards the end of the Classical era, the city was never rebuilt to the glory that it saw under Themistocles

The remains from the Theater of Dionyso

The Theater of Dionyso was the prominent location for any type of events in Piraeus deme. The most common types of gatherings were political rallies and deme assemblies that took place frequently throughout the year. Most notably, the oligarchy coup of 411/410 was the biggest assembly recorded by Thucydides where the hoplites gathered and marched through the city. The theater is located adjacent to the Munichia on the northwest side of Piraeus.